Nobody raises a question on the fact that the 1880s was the epoch-making period in Joseon-Ching Relation (朝淸關係). Traditional Joseon-Ching Relation was Joseon gave tribute to Ching and Ching approved the crown-installation of Joseon; however, Ching began to actively interfere in Joseon politics in 1880s. Especially the military intervention during the Imoh Military Mutiny (壬午軍亂) was an action that essentially change the traditional Joseon-Ching Relation since the Ming (明) dynasty. This new policy of Ching continued and there is an understanding that the Joseon policy of Ching escaped from traditional to quasi-imperialistic policy at this time. There are many studies on this subject; however, there is no study that paid attention to the fact that Beiyang Naval Force (北洋水師) played a decisive role in enabling the active intervention policy of Ching on Joseon. This study follows the new change in Joseon-Ching Relation at the time by focusing on the activity of Beiyang Naval Force in 1880s.
In the main text, the activities of Beiyang Naval Force during the execution of commercial treaties with Western powers, the Imoh Military Mutiny, the execution of Trade Treaty on sea/land by Merchants of Joseon and Ching (朝淸商民水陸貿易章程), the Gapsin Political Upheaval (甲申政變) and Geomundo (巨文島) Event will be explored. For instance, Article 7 of Trade Treaty on sea/land by Merchants of Joseon and Ching defines that Ching will take the responsibility of defending seacoast of Joseon and control its naval ships from Incheon port. Since Joseon did not have modern naval force at the time, Joseon attempted the modernization of country by getting the protection of Beiyang Naval Force. At the time, Zhang Pei-lun (張佩綸) suggested in Article 6 of Joseon Dealing Plan (朝鮮善後事宜) to change military focus from army to navy, build two or three more battleships and dispatch them to Incheon. On this, Li Hong-zhang (李鴻章) tried military domination by designating Incheon as the advance base of Beiyang Naval Force while saying that Shandung and Incheon have the relation of eyes and nose.
In 1880s, Beiyang Naval Force controlled the Yellow Sea and took earlier military action on Joseon than army by dispatching naval force. The army of Ching could not perform even normal activity without the support of navy. Like this, the superior power of Beiyang Naval Force was an important factor in determining the superiority of Ching over Japan in Joseon. It was enabled direct military intervention of Ching on Joseon. The appearance of modern navy, which has the mobility of traveling from Shandung to Incheon in one or two days, caused a crack in traditional Joseon-Ching Relation. Japan was stimulated on the power of Beiyang Naval Force and it focused on the reinforcement of naval force. It consequently created huge change in the politics of East Asia in 1890s.